First, ALD technology addresses the core pain points of solid-state batteries

Solid-state batteries are regarded as the next-generation battery technology due to their high energy density and high safety. However, two major issues, namely the large solid-solid interface impedance and lithium dendrite growth, restrict their commercialization process. Atomic layer deposition (ALD) technology, with its atomic-level precision thin film control capability, has become a key means to break through these bottlenecks. Its core advantage lies in the ability to deposit ultra-thin (nanoscale to sub-nanoscale), uniform, dense and pinhole-free functional films, achieving precise modification and protection of the battery material interface.

Ii. Three Core Applications of ALD in Solid-State Batteries

①1. Cathode material coating: Enhance stability and ion conduction efficiency

Technical principle: A solid electrolyte (such as LiPON, LiAlO₂) or a protective layer (such as Al₂O₃) film is deposited on the surface of the cathode particles to form a physical barrier.

Core values of youdaoplaceholder4:

o Reduce interfacial impedance: Improve the ion conduction path between the positive electrode and the solid electrolyte to reduce charge transfer resistance [^1];

o Inhibition of side reactions: Isolate the direct contact between the cathode and the electrolyte, prevent the dissolution of transition metal ions and the formation of interface by-products, and enhance the cycle life (for example, after the 4.7V high-voltage LiCoO₂ cathode is coated with ALD, the cycle stability is improved by more than 50%).

o Compatible with high-voltage systems: Supports cathode materials to operate at higher cut-off voltages (such as increasing LiCoO₂ from 4.3V to 4.7V), breaking through the specific capacity bottleneck.

②2. Preparation of solid electrolyte membranes: Achieving ultrathin and dense electrolyte layers

<s:1> Technical principle: By alternately depositing precursors with ALD, solid electrolyte films with controllable thickness (10-100nm) and no defects (such as Li₃PO₄, LiNbO₃) are prepared.

Core values of youdaoplaceholder4:

o Inhibiting lithium dendrites: The dense film can physically prevent lithium dendrites from penetrating, reducing the risk of short circuits.

o Compatibility with all-solid-state structure: The ultra-thin feature helps reduce the thickness of the electrolyte layer and increase the volumetric energy density of the battery, which is a key process for the batch production of all-solid-state batteries.

③3. Interface decoration: Optimize the compatibility of multi-layer structures

<s:1> Technical principle: Deposit a "buffer layer" (such as TiO₂, ZnO) or "bonding layer" at the interface of electrode-electrolyte, electrolyte-current collector, etc., to regulate the chemical and mechanical properties of the interface.

Core values of youdaoplaceholder4:

o Improve interfacial compatibility: Alleviate lattice mismatch and thermal expansion differences between multilayer materials, and reduce interfacial cracking [^1];

o Enhance mechanical stability: Buffer the volume expansion of electrodes during charging and discharging (such as silicon-based anodes), and maintain interface contact.

Iii. Market Prospects: From "R&D Tools" to "Mass Production Essentials"

④1. Technological maturity and industrialization progress

At the current stage, ALD technology has moved from laboratory verification to pilot application. Leading battery manufacturers (such as CATL) have purchased ALD equipment for their solid-state battery R&D lines (for instance, Microadmittance Nano signed a 336 million yuan ALD equipment order with CATL in 2021).

The trend in the next 3 to 5 years: As solid-state batteries enter the mass production preparation period (expected from 2027 to 2030), the demand for ALD equipment will extend from the R&D end to the production line end, becoming the "standard process" in solid-state battery manufacturing.

⑤2. Market size and Growth drivers

<s:1> Equipment market: The global ALD equipment market size is approximately 10 billion US dollars in 2025. Among them, the proportion of the new energy battery field is less than 10%, but it has the fastest growth rate (with a compound annual growth rate of over 40%).

<s:1> Materials and services market: Supporting industries such as ALD precursors (such as organolilithium compounds) and process development services will grow simultaneously. It is expected that the market size of ALD related to solid-state batteries will exceed 3 billion US dollars by 2030.

⑥3. Industrial Chain Roles and Competitive Landscape

Youdaoplaceholder2 Core players: equipment manufacturers (such as microadmittance nano, ASM), material suppliers (such as Merck, SAFC Hitech), and technology service providers (such as Institute of Physics, Chinese Academy of Sciences, Jianghan University team) constitute the core of the industrial chain;

Technical barriers: The high-precision control of ALD equipment, the purity of precursors, and process adaptability (such as the large-scale challenge of powder coating) are the main competitive focuses. Leading enterprises have formed a first-mover advantage by virtue of patent layout (such as the technical reserves of micro-conductive nanomaterials in the field of cathode coating).

⑦4. Dual drive of policy and demand

Policy support: ALD technology has been included in China's "14th Five-Year Plan" new materials Special project and the EU's "Battery 2030+" plan, serving as a key supporting technology for the industrialization of solid-state batteries.

Downstream demand: The demand for solid-state batteries in scenarios such as new energy vehicles (with a range of over 1,000 kilometers), consumer electronics (flexible batteries), and energy storage (long cycle life) will directly drive the implementation of ALD technology.

Iv. Challenges and Future Directions

The cost of mass production: The investment in ALD equipment is high (tens of millions of yuan per unit), and the process cycle is long. The unit cost needs to be reduced through the localization of equipment (such as micro-admittance nano) and batch production.

<s:1> Material innovation: Develop ALD solid electrolyte materials with high ionic conductivity (such as sulfide-based films) to further enhance battery performance;

Process integration: Compatible with existing lithium battery production lines (such as roller-to-roll ALD technology), to achieve large-scale manufacturing of solid-state batteries.

Summary

ALD technology has become a "bridge" from the laboratory to industrialization by solving the interface and safety problems of solid-state batteries. In the next 3 to 5 years, as solid-state battery pilot lines transition to vector production lines, ALD will be upgraded from a "research and development tool" to a "core production process", giving rise to a market worth hundreds of billions of yuan in equipment, materials, services and other links. For enterprises, making early preparations for ALD technology research and development and patent reserves will enable them to occupy a strategic high ground in the competition of next-generation battery technology.